rosenberg



1956 c. B. ROSENBERG 2,758,694

CARRIAGE OPENING MECHANISM Filed Feb. 7, 1952 5 Sheets-Sheet 1 IN VEN TOR. C/mmss B. Rose/vases BY ail W 4 ATTORNEYS 1956. c. B. ROSENBERG 2,758,694

CARRIAGE OPENING MECHANISM Filed Feb. 7, 1952 5 Sheets-Sheet 2 "III/III IN V EN TOR.

ATTORNEYS CHARLES fifaoseuaE/ee Aug. 14, 1956 c. B. ROSENBERG 2,758,694

CARRIAGE OPENING MECHANISM Filed Feb. 7, 1952 5 Sheets-Sheet 3 Fig. 3.

/ INVENTOR, CHA RLES B. ROSENBERG ATTORNEYS 4, 1956 c. B. ROSENBERG 2,758,694

CARRIAGE OPENING MECHANISM Filed Feb. 7, 1952 5 Sheets-Sheet 4 THROW BAcrr Sw/rcH E L L; M0704? BAH TPELEAsE RELEASE SW/TcH SWITCH IN VEN TOR. CHARLES B. ROSENBERG BY 9% W 4 (736M ATTORNE Y5 1956 c. B. ROSENBERG CARRIAGE OPENING MECHANISM 5 Sheets-Sheet 5 Filed Feb. 7, 1952 IN V EN TOR CHA mes BRosszvsms BY ATTORNEKS United States Patent CARRIAGE OPENING MECHANISM Charles B. Rosenberg, Royal Oak, Mich., assignor to Burroughs Adding Machine Company, Detroit, M1ch., a corporation of Michigan Application February 7, 1952, Serial No. 270,400

16 Claims. (Cl. 197-128) The present invention relates generally to paper carriage operating mechanisms and more particularly to means readily attachable to existing types of business machines whereby, by a slight modification or the replacement of a single, readily accessible member and without rearranging any of the parts of such machines, the normally manually operable paper carriage mechanism thereof may be rapidly operated by power controlled from a remote point such as the keyboard of the machine.

It has been found in the past that when employing business machines such as, for example, accounting machines wherein the paper carriage throwback mechanism and the front feed mechanism are operated manually, an appreciable portion of the time required by an operator to insert and align paper and to make an entry thereon is taken up by operating these mechanisms. A substantial increase in the amount of work that such a machine could handle would be made possible if means could be provided for rapidly operating these mechanisms by power from a point remote therefrom. Various means have been suggested in the past for doing this but such means have not been generally acceptable because they require rebuilding substantial portions of the machine as well as limiting the basic versatility thereof.

One object of the present invention is to provide novel and simple means readily attachable to existing types of machines for operating the paper carriage thereof by power controlled from the keyboard of the machine.

Another object is to provide a power unit assembly arranged so as to be readily mounted in the field and without special tools upon the carriage of existing types of accounting machines and including means cooperating with the standard parts of such machines to eifect selectively the various desired conditions of the paper carriage thereof by manipulating control elements disposed on the keyboard of the machine.

A more specific object of the invention is to provide an electromagnetic power assembly for mounting directlyon the traveling carriage of an accounting machine and arranged to engage and cooperate with the standard parts thereof to move the paper carriage to its throwback position, to open selectively the front feed throat of the machine as an incident to the throwback movement of the carriage and automatically lock the paper carriage in its throwback position, and to close the front feed throat and release the paper carriage, all controlled from a control unit disposed at the keyboard of the machine.

A still more specific object is to provide a conversion kit for existing types of accounting machines having manually operable paper carriage throwback and front feed operating mechanisms, whereby without modifying any of the essential elements of the machine or their functions, these mechanisms may be operated by power controlled from the keyboard of the machine.

These and other objects and advantages of the present invention will be apparent from the following specification taken together with the accompanying drawings ice wherein one embodiment is illustrated by way of example and in which:

Fig. 1 is a left-side elevational view of an accounting machine embodying the invention;

Fig. 2 is a perspective view of a portion of the paper carriage having the novel power throwback and front feed operating mechanism applied thereto;

Fig. 3 is a cross-sectional view taken along line 3-3 of Fig. 2;

Fig. 4 is a perspective view of the control switch assembly for mounting on the keyboard of the machine;

Fig. 5 is a diagram showing how the various control elements are connected in circuit with the power supply; and

Fig. 6 is a perspective view of the mechanism for operating a release switch from the motor bars.

For a better understanding of the invention it will be described as applied to the well-known Burroughs Moon- Hopkins billing machine of the type disclosed and described in U. S. Patent 1,336,904 to Hubert Hopkins. It will be understood, however, that the invention is applicable to various types of accounting machines having a displaceable paper carriage whether they be of the under strike type as illustrated or of the well-known front strike type.

General features The machine illustrated is a typewriting and ten-key calculating machine wherein the typewriting section generally indicated at 10 and the calculating section generally indicated at 11 are controlled by keys 12 and 13, respectively. The calculating mechanism includes the wellknown actuator racks 14 carrying type 15 in which the calculating machine type are carried. The actuator racks cooperate with a registering mechanism 16 to extend the type bars underneath and horizontally past platen 17 so that the type positioned along the printing line may be struck by printing hammers against the platen as described in the Hopkins patent referred to above. The calculating mechanism is operated by means of an electric motor 18 through a suitable clutch and drive mechanism such as, for example, disclosed in U. S. Patent 1,025,698 to Hubert Hopkins. Inasmuch as the present invention relates only to specific elements of the machine, only such portions of the machine will be described in detail as are necessary to fully appreciate the true nature of the invention.

The machine is provided with a conventional traveling carriage which is mounted on the machine in the usual manner by means of a pair of spaced parallel guides 21 supported on a pair of corresponding guides 20 on the machine frame by means of a suitable anti-friction arrangement such as balls 22 confined within race ways disposed in registering faces of the guides. End plates 23, of which only the left hand plate is shown in the drawings, are secured to the respective ends of the guides 21 and of the square cross shaft 24 so as to form a rigid assembly.

The carriage supports in the usual manner the platen assembly comprising a platen frame pivotally mounted on the carriage and supporting platen 17 as well as the equipment for holding the record or journal sheet and the individual ledger sheets or cards. The carriage and the paper holding equipment may be of the construction shown in U. S. Patent 1,774,287 to R. L. Muller to which reference is made for a more detailed description thereof. The platen frame comprises generally a pair of spaced parallel platen frame end plates 25 of which only the left hand one is shown in drawings, a cross shaft 27, and a pair of cross rods 26 which serve as means for mounting the guiding bands for the journal sheets as shown in the last named, Muller patent. Platen 17 is secured to platen shaft 28 which is journalled for rotation in platen frame end plates- 25, and knobs 29 are secured to the respective ends of the platen shaft for manually rotating the platen.

The platen assembly is swingabl'y mounted on cross shaft 30 which extends between carriage end plates 23, by means of at least two spaced links 31' having the ends thereof rotatably mounted on the last mentioned cross shaft and the platen frame cross shaft 27, respectively, as better shown in Fig; 3'. The usual springs 311i for permitting the carriage to be moved forwardly with re spect to its normal printing position are provided. These springs are secured to respective ones of links 31 and are formed seaso? engage cross shaft 32', also mounted between end plates 25, and are tensi'oried so as to norposition the platen assembly so' that shaft 32 is held against the side of the links. Rearwardly' extending lugs 33 on end plates 25 rest against a stop member 34 carried by the rear carriage guide 21, when the platen frame is in its normal printing position.

Spring member 36 is secured to cross shaft 32. and has rotatably mounted thereon the usual feed or pressure rollers 35. The pres'sure rollers extend through openings provided in shield 37 which is held in lace by means of extensions thereof bent over carriage cross shaft 30. 'rhe piar'enassembly may be swung about cross shaft 30 by means of the interconnecting links 3'1 from the printing'position' illustrated in Fig. 2 wherein a forwardly extending finger 25a of end plate 25 will rest upon stud 23a depending from carriage end plate 23, to the throwback or reading position indicated in Fig. 3 wherein-.21 roller stud 38- mounted on end plate 25 and extending to the left therefrom as viewed in Fig. 2 will rest against a stop plate 39 mounted on square shaft 24.

.I-n many types of calculating machines now in use the platen; frame is moved from the printing position to the throwback position by means of a handle attached to one or both of platen end plates 25 such as, for example, indicated by reference number 15 in Fig. 2 of U. 8.. Patent No. 2,055,551 to R. L. Muller, and in others the platen frame is moved by means of a linkage connecting it with a manually operable lever mounted on the front of the machine.

Mechdl iisin' for movihg the platen to throwback position In accordance with the present invention there is provided power means readily attachable to existing types of calculating machines and controlled from the keyboard of the machine for displacing the platen frame from a normal printing position such as that shown in Fig. 2 to a throwback position such as that shown in Fig. 3 independently of the cycling operation of the machine. To this end, the power unit generally indicated at 40 is rigidly mounted on the lefthand carriage end plate 23 by'mea'ns of threaded studs 41 extending therefrom subs'tantially parallel to the axis of rotation of the platen frame-r The power unit 40 comprises a linear solenoid 42. and a rotary solenoid 43' mounted on a common mounting plate 44. Secured to the mounting'plate andextending perpendicularly therefrom for engagement with studs 41 are a pair of studs 45 whose free ends' ar'e provided with collars for engaging an inwardly extending shoulder on eachof coupling nuts 46 carried bythe studs for engaging the threaded ends of mounting studs 41.

Rotary solenoid 43 is mounted on plate 44 by means of apair'of threaded studs 47 ex ending through the plate and through spacing bushings 48 and secured in place by'rneans of sleeve nuts as shown. The solenoid power shaft 49 extends through an opening in the plate and the axis of rotation thereof is preferably parallel with the: axisof rotation of the platen frame; Solenoid 43 may be of the type generally available on the market under the trade name of Ledex Rotary Solenoid. This type of solenoid is constructed so as to rotate the power shaft and the lever mounted thereon through a predetermined angle, in the present example an angle of 67.5, with an axial displacement in the order of .050". One advantage of this type of solenoid for this particular application is that the initial torque thereof is considerably greater than the torque developed during the final portion of its movement.

For the purpose of mechanically coupling the power shaft to the platen frame to raise it to throwback position when: the solenoid is energized, there is provided a main power lever 5h which is securely mounted on the shaft so as to extend at substantially right angles therefrom.- The power lever 59 comprises generally a cam portion 51 and a sectorial plate portion 52 extending radially in opposite directions from the shaft. The lever is mounted on the solenoid power shaft so that the cam portion thereof will just contact a sleeve or bushing 53 which is rotatably mounted on platen shaft 28 to permit rolling contact between cam portion 51 and sleeve 53 andto permit free axial movements of the solenoid power sha'ft. Cam portion 51 is so' formed that initial rotary moveme'n't of shaft 49 will cause the platen frame to be moved forwardly a distance sufhcient to enable shaft 28 to clear a printing latch 54' mounted on carriage end plate 23, and then swing the platen frame along anarc to its throwback position; The printing latch 54 is provided in order to form a positive stop for the platen frame to" prevent it from moving upwardly during the printing ope ration v In order to" lock power lever 50 in operated position wherein it will hold the platen frame in a throwback position, there is provided latching plate 55 having a pair of spaced'openings therein for receiving spacing bushings 48 on moilnting studs 47. The latching plate is biased against the nuts on studs 47 by means of compression springs 56 and will tend to assume a position parallel with the mounting plate 44 and the sectorial portion 52' of lever 50". The latching plate is provided with a latching lug extending outwardly from the plate and arranged so that it is normally urged against lever 50 and will engage edge 58' thereof when solenoid 43 is energized and the lever is rotated in a clockwise direction as viewed in Fig. 2.

In order to release this latch when solenoid 42 is-energized and in order to open the front feed throat of the paper carria'geas an incident to raising the platen frame to a throwback position, there is provided amechanism generally indicated by reference numeral 60; This mechanism comprises a plate member or standard 61- having a ybkeportion thereof straddling studs 45 and held in engagernent therewith by means of recesses 62 opening towardsthe rear'of the machine. A retaining'pl'at'e or clip 622i is positioned between the legs of the yokeportion of the plate member and secured by means of a screw, for example, as shown, to the plate member in orde'r't'o prevent sidewis'e' movements thereof with respect toits sup port. The plate member is maintained in an upright generally vertical position by means or compression springs 63 biasing the plate against the sleeves of coupling nuts 46: An armature 64 is mounted near the upper end of the plate iniuxtaposed position with respect to the magnetic yoke 65"of solenoid and normally spaced'ashort dista'n'c'e therefrom. Also mounted near the upper end of member 61am on the opposite side thereof is a roller 66- which normally is in alignment with a front feed throat opening arm 67 secured to' the end of a shaft 68,and which will be" engaged by the arm to cause the shaft to rotate to thereby open the front feed throat of the machine through a linkage which will be described in detail herein-- after; Shaft 68*is journalled in platen frame end plate 25 and a braeket 69- secured to the end' plate and'bent so that the end wherein the shaft is j'ouriialled is spaced from thoend plate; I'nterposed between bracket 69 and the plate 215 is a short sleeve 70 fastened to theshaft by the 11s of set sere'vvs to permit axial adjustments of shaft S 68 with respect to plate in order to align arm 67 with roller 66.

When the platen frame is to be lowered from its throwback position with open feed throat, it is important that the feed throat be completely closed to secure the newly inserted record therein prior to lowering the platen frame. To this end the invention provides means whereby the frame latch releasing mechanism is actuated as an incident to closing the front throat and will not take effect to begin to lower the frame until after the feed throat has been closed. This is accomplished by providing a frustoconically shaped roller 71 rotatably mounted on a bracket portion 72 extending at right angles from latching plate so arranged that arm 67 will engage the right hand conical surface of the roller to displace it and consequently plate 55 to the left as viewed in Fig. 2 when roller 66 is moved out of the way to the left.

Shaft 68 is operatively connected to the feed throat mechanism through a lever 75 mounted on the shaft on the opposite side of plate 25 with respect to arm 67 and carrying a roller 76 normally resting on an outwardly extending manually operable arm 77 of throat actuating lever 78. Lever 78 is secured to shaft 32 which carries the pressure rollers 35 and when outwardly extending arm 77 is depressed, it will cause lever 78 to rotate shaft 32 connected thereto thereby swinging the pressure rollers away from the platen. Lever i5 is provided with a heel portion 79 extending over the mounting bushing 80 for the front shaft 26 for preventing shaft 68 from accidentally assuming an inoperative position wherein levers 67 and '75 will extend to the left instead of to the right as viewed in Fig. 2. A tension spring 81 engaging a downwardly extending arm 82 of lever 78 biases the lever in a clockwise direction as viewed in Figs. 2 and 3 and causes rollers 35 to press against platen 17.

The control switch assembly for operating the throwback solenoid 43 and the release solenoid 42 is shown in Fig. 4 and the manner in which it is mounted on a Burroughs Moon-Hopkins billing machine is indicated in Fig. 1 wherein a portion of the keyboard is shown broken away to show the position of the control switch assembly which is mounted on the right hand side of the keyboard. The control switches are enclosed within a cover 85 indicated in dotted lines in Fig. 4 mounted on a post 86, which is normally provided on the machine at the right side of the keyboard as a guide for the horizontally moving error key 87. The switch assembly comprises a supporting yoke 38 secured to post 86 between the cover and the post.

The yoke and the cover may be mounted on the standard error key post by providing a tubular, bushing-like member 98 having preferably an outside diameter equal to that of the post and having a shoulder and a reduced diameter portion extending therefrom at its upper end. The yoke and cover are provided with an opening of sufilcient size to receive the reduced diameter portion of the bushing-like member which may be spun or riveted down on the top of the cover forcing the under side of the yoke against the shoulder to permanently secure together the cover, yoke and bushing-like member. The assembly may then be secured to the post 86 by means of a fastening screw 93a passing through the bushing-like member 98 and screwed into the threaded opening in the end of the post. The yoke is provided with a pair of downwardly extending ears 89 having journalled therebetween a cross shaft 90, and a pair of laterally extending ears 91 having tension springs 97 connected thereto. A pair of switch housings 92 and 93 having secured therein mercury switches 94 and 95, respectively, are pivotally mounted side by side on shaft and are maintained in position thereon by means of spacing sleeves 96. The shanks of a pair of keys and 101 extend through sleeves 102 of cover 85 and have the lower ends thereof slotted to receive arms 103 and 104 of housings 92 and 93, respectively. Springs 97 are connected between housings 92 and 93 and respective ones of ears 91 and iron mally bias the housings to the position indicated by housing 92 in Fig. 4 wherein the keys will be extended upwardly and the contacts of the switches will be open. When the keys are depressed to the position indicated by key 101 of Fig. 4, the associated switch housing will be tilted to the right to assume the position indicated by switch housing 93 and the contacts of the switch associated therewith will be closed.

In order to cause the platen frame to drop to printing position when the motor bar of the machine is actuated, there is provided an auxiliary release switch 105, Fig. 1, pivotally mounted on the frame of the machine and normally tilted to the right so as to maintain the contacts thereof in open condition. As better shown in the detailed view of the motor bar assembly in Fig. 6 as viewed from below, motor bars 106 and 107 are supported on motor bar yokes 108 and 109, respectively, rotatably mounted on motor bar cross shaft 110 journa'lled in the machine housing. The machine may be provided with as many as four mot-or bars but only two are shown in the drawing. Fixed to .the cross shaft 110 is a main control member 1111 connected to the machine clutch by means of a rod 112. Control member 111 is provided with a downwardly extending arm 113, of which only a portion is shown, for operating a locking slide (not shown) for interlocking the result keys in the manner described in U. S. Patent No. 1,920,477 .to Robert L. Muller and illustrated in Figs. 1 and 3 thereof. Cross shaft 110 is operatively connected to the several motor bars by means of an upwardly extending .arm '1'14 provided on each of the motor bar yokes and which carries a stud 115 adapted to engage a lever 1'16 fixedly mounted on the cross shaft. When one of the motor has is depressed the cross shaft will be rocked in a clockwise sense as viewed from the left in Fig. 6 and will move the control member 111 mounted thereon to start the machine.

Control member 1111 is also provided with a downwardly extending arm 117 passing through an elongated slot in the bottom plate 118 and through an aperture 119 in a slide 120. Slide 120 is 'slid'ably mounted on the under side of plate 118 by means of a stud which passes through a slot 121 in the slide and which is provided with an enlarged head 122. The slide is connected to a crank which in turn is operatively connected by means of a link -124 to a tabulator interlock (not shown) but normally located at the left side of the keyboard for preventing hand tabulation when a motor bar is depressed. A crank 125 is movable into the path of a lug 1126 on slide 1120 in order to prevent movement of the slide and thus lock the motor bars when the carriage is traveling following a machine operation. The motor bar mechanism so far described is normally provided in the standard type Burroughs Moon-Hopkins billing machine.

Auxiliary release switch 105 is detachably held in a spring clip 127 attached to an arm 128 which in turn is secured to the left hand end of a rotatable shaft 129. Shaft 129 is journalled in a pair of brackets 130 mounted on the under side of the machine by means of a pair of screws 131 (only one is shown in the drawing) which are normally provided for securing bottom plate 118 to the frame. An actuating arm 1-32 is secured to the other end of the shaft and is engageable by lug 126 on slide 120 when the slide is moved rearwardly by a motor bar. Arm 132 will not interfere with movements of crank 12:5.

It will be apparent that when one of the motor bars is depressed, arm 1117 will cause slide .120 to move rearwardly and, through engagement of lug 1126 with arm 132, will cause shaft 129 to be rotated in a counterclockwise direction as viewed from the left in the drawing. Such rotation of shaft 1'29 will :cause switch 105 to be moved from the open contact position shown wherein it is tilted downwardly toward the front of the machine to its closed contact position wherein it will be tilted in the opposite direction. A spring '133 is connectedbetween the left 7 hand bracket F130 andarm +1.28 to bias :thesw-iteh assembly'to the position-shown.

ife eyclihg mechanism of calculating machines is nsually-:oper'ated bywalternatin'g current and in ?order to provide -D. C. operating power for solenoids '42'and 43 there is provided a full Wave rectifier unit-generallyindicated at 140 suppc'irted by a bracket 141 mounted on the name of the machine as indicated in-Fig. 1. The-rectifier unit 140 comprises four rectifiers 142 connected ii 1 a= conventional bridge. A"mercury sw itch 143 is tmouhtedbn bracket =14=1 insuch aposition that its contacts wilYbe closed when the: machine is in its normaioperative posit-ion-shownih Fig. 1, but will be opened when the machine is til'ted-backwardly for-servicing. A terminaluboa'rd 1144 for connecting the various components ofcthe-eleetniea'l circuit togethenis also mounted 'on bracket 141.

- t me manner in which the arious electrical components are connected in the'cir'cuit is *ill'nstrated in Fig. 5. The rectifier 'br idge 1 40 is connected*to the'aiternating current supply throilgh the normally'closed switch 1 43 andthe rectified voltage-5s applied acrossderm'inals Q and set terminal board 144. The energizing-windingaof solenoid 43 and-a condenser .1 45 are "connected across terminals 1 andi and the energizing windihg of s'olenoid 42 is connect'ed acros's terminals z and 4. Motor bar release switch 105 and l'a-tch 'releaseswitch94 -are connected in parallel across-terminals 3 "and *4 and the throwback switch 95 is connected across terminals 1 and '3.

Gperafidn -(-lomingnow-to the description ofthe operation of the invention, it will first be assumed that the platen frame is in-the'position shown in Fig. 1 and that it is desired to raise it tothrowbackposition with the-front feed throat open-for replacing the recordsheet.

The "operator merely depresses throwback key 101 whereby-switch housing--93 will be pivoted ina clockwise direction asviewed in -Fig. 4 against'tension spring97. This-willcause the fluid mercury in-switch 95 to flow to theconta-ctend thereof to bridge the contacts. Referring now toFig. 5--it will be noted that'closing the contacts of switch 95 will connect terminal '3 of terminal board 144 to terminal =1 to connect the output of rectifier bridge .140 across the energizing winding of solenoid '43. Solenoid 43 will operate. andrcause shaft 49 and hence lever 50 to rotate'ina clockwise direction as viewedin Fig. 2. As it was noted above-cam 5-1 of lever 50 is formed-soas initially to move shaft 28 and hence the platen frame attached thereto forwardly a distance sufficient to clear printing latch 54 and then upwardlyalong an arc of travel asdefinedby the cam configuration of the front edge of stop plate 39and guided by roller 38 traveling along. and in engagement with this front edge. The platenfr-arne reaches its limiting position when roller 38 abuts the dwell or stop profile of the stop plate. By this time edge 58. oflevert'50 will: have cleared offset latching lug '57 of latching plate SSJand the latching-lug will engage this edgevtoprevent the platen frame from-falling back when key- 101-is released and solenoid 43 is deenergized.

.Asihepla-ten frame is moved -to throwback position, cam 67 will engage the under side of roller 66 on the stationary rupright-member-6l to rotate shaft 68 and thereby 'cause pressure rollers 35 to be moved away from platen 17 tothe position shown in Fig. 3 in a manner which willnow be described Thecarn 67 is so formed andpositioned that as the platen-is lifted, the cam will engage the under side of roller 66 to rotat'esha-ft 68 secured thereto in a clockwise direction with respect to thepl'atenfr'ame until the cam reaches the position indic'a'tdin' Fig. "3. Th'epro'gfe's'sive tilting of earn '67 as the piaren frame is liftedcauseda corresponding rotation of lever "75"coiinecfedto the'o'ther end at shaft 68. Roller tormented on means-er lever 75 normally iu's't Tests 5 iristar'r'n 77- ef' throat eontrolling reviews. As -'-lever l's iszeetste'd, roller '76 will: bear inst ar-m 77 to tilt ievems areeumereleckwise direction-against tension sptingSI. -Rotation-of lever 78 will-cause a correspond,

ing rotation of cross shaft 32 on which it is mounted 'as well as of the spring support '36-and the pressure roller 35 also -depending from this shaft. Thus, as the platen frame moves from its printing position toits throwback position, thepressure rollers 35 will be moved from a position'wherein they clamp the record against the platen to a position-wherein they will be separated therefrom to enable the operator to replace the record. Shield 37 is loosely held over cross shaft 30 and will follow the movements of spring member 36. Thespace between shield 37 and platen 17 is known in the art as the front feed throatinasmuchas the records are placed therein and removed therefrom from the front of the machine.

After the-record sheet has been replaced and-it is desired to drop the platen back to printing position, :key is momentarily depressed to close the contacts of switch 94 controlled thereby. From Fig. 5 it will be noted that when the contacts of switch 94 are closed, terminals -3 and 4 of terminal board 144 will be interconnected to connect the output of rectifier bridge 1-40 across the energizing windings of solenoid 42 to energize it and attract armature 64 mounted on upright member 61. This will displace roller 66 to the left, as viewed in Fig.2 and out of engagement with cam 67. Cam 67 will therefore move against the right side of the coneshaped camming surface of roller 71 to force it toward mounting plate 44 under the action 'of pressure roller biasing-spring 8-1 through levers 78 and 75 at the same time as the pressure rolls 35 are permitted to move against the platen. The movement of roller 71 will cause latching plate 55 to tilt against the force of springs 56 to move latching lug 57 out of engagement with lever 50. The platen frame is now freed and will fall'by its own weight, depressing printing latch 54 against its.return spring which will cause the latch to return to the latchingIpo'si-tion shown in'Fig. 2 when the platen frame reaches its printing position wherein the forwardly extending finger 25a will engage stud 23a. It will be noted that the front feed throat of the machine is closedto clamp the newly inserted record sheet in place against the platen before the platen frame is lowered.

The latching lug 57 holding the platen frame in throwback position will also be released to drop the platen frameainto printing position when one of the motorbars is actuated. It will be noted from Fig. 5 that switch is connected in parallel with releaseswitch 94 and closing switchltiS will have the same effect as closing switch 94. As described above ail the motor bars are operatively connected with a downwardly extending arm 117 which is connectedto slide 120 so as to move the slide to theleft as viewed in Fig. 1 when one of themotor bars is actuated. Thus whenever one of the motor bars is depressed, slide 1-20 will be caused to move to the left and thereby tilt mercury switch 105 down toward the left to close the switching contacts thereof. This in turn will energize solenoid 42 to release the platen frame if it is in its throwback position thereby permitting it to drop to printing position as explained above. Actuation of the solenoid 42 through operation of the motorbars during normal use of the machine will of course have no effect upon the normal functions of the machine.

If it is desired to raise the platen frame to view previously printed figures without opening the front throat, keys 1'00a'i1d 101 are either simultaneously depressed or key 100 is first depressed and held down while key 101 is depressed. Depression of key 100 will close switch'94 and energize latch'releasing solenoid 42 to attract armacure-"64 'mourit'ed on upright supporting member 61 and will 'inove'roller'66 'tothe left out of the path of cam 67. Depression of key 101 will raise the carriage to a throwback position as explained above, but as roller 66 has been meve'd 'out of the path or cam '67, this ca'm'will "engage latch releasing roller stud 71 mounted on latchin'g plate SS' and move the plate to the left'so as to maintain latching lu'g 57 "out of engagement with lever 50.

. 9 Thus the platen frame is moved to throwback position without opening the front feed throat and without being locked in throwback position and is maintained in such throwback position only as long as the two keys 100 and 101 are depressed. As soon as the keys are released, the platen frame will drop to normal printing position.

Cut-out switch 143, shown in Fig. 1, is provided in order to open the energizing circuit for the solenoids when the machine is tilted backwardly for servicing. Backward tilting of the machine will of course cause switches 94, 95 and 105 to close due to the fact that the mercury therein will flow to the contact ends thereof, but at the same time cut-out switch 143 will open to disconnect the rectifier from the A. C. power supply. The cut-out switch is mounted so as to remain closed in normal operating positions of the machine wherein switches 94, 95 and 105 will be open.

Condenser 145 is permanently connected across solenoid 43 in order to stabilize the operation thereof but no condenser is needed for the less powerful solenoid 42.

An important feature of the present invention resides in the fact that the various component parts thereof may readily be mounted on existing types of calculating machines or typewriting machines generally and particularly the Burroughs Moon-Hopkins billing machine referred to above and which has been illustrated in the drawings. The only part in this latter type of calculating machine which has to be modified is the platen frame stop member designated with reference numeral 18 in Fig. 4 of the above mentioned U. S. Patent No. 2,055,551 to R. L. Muller. This stop member has in the past been used for the dual purpose of limiting the throw of the platen frame as well as maintaining it in throwback position. When used with the present invention, the stop member 39 is formed so as to merely act as a stop for limiting the backward movement of the frame but will not prevent it from falling down to printing position by its own weight when the latching mechanism is released by energizing solenoid 42 as explained above. It may be preferable to provide a second stop member 39 on the right hand side of the carriage in order to stabilize both ends of the frame. By properly forming the front cam surfaces of these stop members, the frame member will be positively guided throughout its entire movement between throwback and printing positions through engagement of roller studs 38 with the cam edges.

The machine may, if desired, readily be arranged to control the carriage opening mechanism by the carriage itself. Thus throwback switch 95 or a switch similarly connected in the circuit may be mounted on the carriage or on the frame of the machine so as to be actuated to open the carriage automatically when the carriage moves into a preselected columnar position.

The mounting ear 99 extending from the rear of the control box cover 85 may be fastened to the right hand side of the machine by means of a mounting screw passing through a mounting hole located in the side panels of the typewriter case portion of the machine and secured by a nut.

Arm 77 of pressure roller controlling lever 78 may be manually depressed in order to adjust the work sheet on rare occasions when this is necessary or when installing a new journal.

Bracket 69 may conveniently be mounted on plate 25 by screws passing through holes provided in the plate for mounting the old hand throwback lever usually provided in the Burroughs Moon-Hopkins type billing machine referred to above.

Although mercury switches were used in the above described preferred embodiment of the invention because of their long life and dependable operation, it will be evident to those skilled in the art that other types of switches, whether they are gravity operated or not, may be used in their place if the actuating mechanism therefor are properly redesigned.

10 I claimi 1. A machine of the class described having a movable carriage, a platen frame pivctally mounted on said carriage and movable between a printing position and a throwback position, a front feed throat operating mechanism, electromagnetic means mounted on said carriage, means for coupling said electromagnetic means to said frame to move said frame from said printing position to said throwback position when actuated, manually operable switching means for connecting said electromagnetic means in circuit with a source of energization, means responsive to movements of said platen frame to actuate said front feed throat operating mechanism as an incident to such movements and means selectively operable to disable said actuating means for said feed throat operating mechanism to permit said platen frame to be moved to its throwback position with said throat in normal condition.

2. In a machine of the class described having a movable carriage, and a platen frame mounted on said carriage movable from a printing position to a throwback position, first electromagnetic means coupled to said platen frame and adapted, when energized, to move said platen frame from said printing position to said throwback position, latching means automatically latching said platen frame in throwback position, second electromagnetic means operatively connected to said latching means and adapted, when energized, to release said latching means to permit said platen frame to assume normal printing position, and first and second switching means actuated from the keyboard of the machine for selectively connecting said first and second electromagnetic means respectively, to a source of energization.

3. In a machine of the class described having a movable carriage, and a platen frame mounted on said carriage and movable between a printing position and a throwback position, electromagnetic means mounted on said carriage coupled to said platen frame and adapted, when energized, to move said platen frame from said printing position to said throwback position, latching means automatically locking said platen in the throwback position, second electromagnetic means mounted on said carriage and coupled to said latching means and adapted, when energized, to release said latching means to permit said carriage to fall to its printing position by its own weight, switching means for connecting said first named electromagnetic means in circuit with a source of energization, and second switching means for connecting said second electromagnetic means in circuit with a source of energization.

4. In a machine of the class described having a platen frame movable between a printing position and a throwback position, and a record-receiving feed throat movable between a closed-throat and open-throat condition, means for opening said feed throat as an incident to throwback movement of said platen frame comprising an actuating arm pivotally mounted on said frame, means coupling said arm and said feed throat to cause said feed throat to open in response to pivotal movement of said arm with respect to said frame, arm engaging means mounted on said machine and disposed in the path of said arm as said platen frame is moved from printing to throwback position to cause said arm to rotate with respect to said platen frame to open said feed throat and means operably connected to said arm engaging means for selectively moving said arm engaging means out of the path of said arm to permit movement of said platen frame to throwback position with said feed throat remaining closed.

5. In a machine of the class described having a travelling carriage, a platen frame movable between a printing position and a throwback position, and a record-receiving feed throat on said platen frame movable between a closed-throat and an open-throat condition, an actuating arm pivotally mounted on said platen frame, means coupling said arm with said feed throat to cause said throat to open in response to pivotal movement of said arm with respect to said frame, arm engaging means mounted on Saidaoarriage; and disposed in the. path of said; arm as the platensframe isrnoved from its printing; position. to its throwback. position tocause said arm torrotate. with respectto said platen frame to open said;feed.-thro.at, and meansrfor selectively. displacing said arm-engaging,- means out of thepath of said arm.

6; In amachine. of the class described. having-a travelling carriage-andaplaten frame. mountedon said carriagev for movement between, a printing-position and a throwback position, power means coupledto said platen frame andadapted, when energized, to displace said platen frame from-its printing position toits throwoack position, means. for; automatically latching said platen frame .in saidthrowback. position, latchreleasing meens,. front-feed means movable-from elosedrthroat toopenrthroatoondition and vice-versa, resilient means operatively. connected to said front-feed means to urge said front-feed means toward closed-throat. condition, means operatively connectedwith saidfronhfeedmeans and effective tocause said frontfeed means. to. assume-its open-throat condition against the force of said resilient means as an incident to the throwbacle movement of said platen frame, power means coupledtto saidfront-feed throat-openingmeans and. adapted, when energized, to render said front-feed throat-opening means ineffective, and means arranged for engagement with saidlatch releasing means and movable with throat movements of said front-feed means to engage said latch releasing means to release said platen. frame latching means as an'incident to the throat-closing: movement of: said-front'feed means effectuated by said resilient means.

7. In a machine of the class describedhaving arplaterr frame movable between a printing position'and a throw back position, power means coupled to said platen framt and operable independently of a machine cycle-to. move. said platen frame from said printing position tosaio throwback position, latching means automatically latch ingsaid platen-frame in its throwback position, front-feed means for receiving andholding awork sheet iniront-feedposition, said front-feed means being movable-from closed to open throat condition and vice versa, resilient means forbiasing said front-feed means toward closed-throat condition, an armpivotaly mounted on said platenframe and coupled to said front-feed means to control throat movements thereof, an arm, reaction'element engagejable: by-said arm upon movementof said platenframe. from; printing position tothrowback position to'pivot' said arm. and opensaidthroat as an incident to such movement: of said frame, power means operable, when energized; to disengage said arm reaction element from said arm, and latch releasing means engageable by said armuponsaid. arm being disengaged from said arm reaction element: andca-usecl to-rotate under theinfiuence of ,saidmesilienti' means urging said front-feed means to a closed-throat condition.

8; Amach-inc; of the class described havin-gatravelling: carriage,- a. platen frame mounted on said carriage for, movements between a printing position and athrowback position, power means functioning independently of: the. cycling. operation of the machineand coupled to said platen. frame to move said platen frame fromprinting-position tothrowback position when: energized, latching; means: automatically locking said platen frame. inlthrow-hack p.o.- sition,- front-feed means having a feed throat: movable. between a'closed throat and open throat condition, resilient; means, for normally biasing :saidfrontzfeedzzmeansr toward closed throat condition, mechanisnrincluding; a rotatable actuating shaft to'operate; said:front feechmeans, an arm mounted on said shaft: for rotation therewith; arsta'ndard; mountedonsaid carriage, arm engaging means mounted: on sa-idstandard and arranged tobe engaged by said armtorcanse said shaft to be rotatedwso astoopensaidzfeedi throatagainst the-biasing force of said=resilient means; upon s'aid platenframe being moved-to its throwbaclepoe siti'on; latch releasing means including: an. actuatingpora 0.11; arrangedzin; the pathofsaid arm-but nqlfmtl ly P vented from. engagement therewith by said, arm: engaging means: interposed 1 therebetween; and meartsfor; selectively. displacing-said arm engagingmember to-permitsaid arm; when the platenframe is in; throwback. position; to be. moved under-the influence of said throat. closing. biasing; means. to:engage said actuatingportion of; said:latoh re leasing meansto release said latchingrmeansasan incident: to, closing said frontfeed throat thereby permitting saidplaten frarneto fallidownby ltSFOWIl weight toits-pn'nting: position; after said feed, throat has beenclosed.

9. A machine of the class described comprising a travel? ling.- carriage, a'platen framemountedonsaid carriage for: movements between a printing position and. a throwback:

- position, a: rotary solenoid having. high initial. torque:

mounted on said. carriageand arrangedto operate inde pendently of the cycling operation-of! the machine, lever: means for'coupling said'solenoid torsaidplaten-frameto move saidplaten framefrom printing position. tothrowback positionupon said solenoidbeingenergized, means. for selectively energizing said solenoid from:- the keyboardiof themachine, latching means automatically lock ing; said. platen frame in throw-back position, front feedi means having a feed throat movable. between a. closed throat: and. open throat. condition, a biasing spring for: normally. urging said front=feed meanstoward closed: throat condition, mechanismrincludinga rotatable actuat ing shaft tooperatesaid front-feed means and a. throat operating arm mountedon saidshaft for rotation there with, a standardmounted onsaidcarriage,.armenga-gingmeans mounted on said standard; and arranged I to be en-- gaged;b.y said .armtolcause. said shaft to be rotated-so as togopen said feed throat against the biasing force of: said: spring during. the throwback movement. of said. platen frame, .latch releasing means including: an actuating. por-- tionzarrangediin thepath-of'said arm butnormally pro-- ventedfrom engagement therewithby saidarm engaging means; interposed therebetween, a linear: solenoid mounted F on saidcarriage,. an armature for. said linear: solenoid mounted; on said standard for displacing said standard and said arm engaging means mounted thereon, when said linear solenoid is energizedtopermitisaid arm, when the; platen-frame. is in throwback position, to -be movediund'er: the influence. of. saidthroat closingbiasin g spring to engage said; actuating'portion of said latch releasingmeans to release said latching means as an incident to closing: said frontrfeed. throat thereby. permitting .said' platen fr-ame to fallQclown-hy its ownweightto' its printing position, and means; for selectively energizing saidiline'arsolenoid from: the; keyboard of the 1 machine.

10. A, kit for readily modifying anaccounting-ma-- chine of thetypeinclnding a platen. pivotal'ly mounted on a travelling carriage'andhavin-g arnanuallyoperable platen throwbackmechanism. and a threat: operating mechanism, so that these mechanisms may :beoperated by; power controlled from r the keyboard of the machine, comprising: a power unit readilyattachable to: -t-l1'e'carriage and-including power means tor -engagingthe. platen frame and adapted, when energized, to cause said-plated frame .to be raiseditothrowback po-sition, latching means for latching"sa-id'platen-frame in said-throwback position, latch releasing-means, mechanism for'coopera-ting with the existing manually operable throat controlling lever of the throat. operating mechanism and adapted i to depress said lever to open said: feed throat as. an incident to the throwback. movement of. said, platen. frame, second: power; means. operatively connected tosa-id lever; dc-. pressing mechanism and adapted, when energized, to. render said last named. mechanism ineffective to; con.- trol said, lever,. and] means; responsive. to the: closing. movement of-thefront feedthroat, when the platen frame.- is. in latched: throwback position, .to. ,actuate .said. latch releasing -means;. aswitching. unit. for: mounting. on, the; keyboard of llhCT machine comprising: a: first and. a second switching means connected. in the. energizing,

circuit of said first and said second power means of said power unit, and manually operable keys for selectively operating said first and secondswitching means; a power supply unit including rectifying means connected in circuit with said first and second power means and the switching means therefor and adapted to be attached as a unit to the machine; and cam means for limiting the throwback movement of the platen frame without retaining it in throwback position to replace existing cam means of the machine normally adapted to limit the throwback movement of the machine as well as to retain it in throwback position.

11. A kit according to claim which further comprises auxiliary switching means for mounting on the machine and including means for mechanically connecting said switching means to the motor bar of the machine to close upon said motor bar being actuated, and means for electrically connecting said auxiliary switch in shunt with said second switching means.

12. A kit according to claim 11 in which said switching means comprise pivotally mounted mercury switches and which further comprises servicing lockout switching means comprising a mercury switch connected in the main energizing circuit and included in said power supply unit and mounted so as to be normally closed when said machine is in normal operating position and to be opened to deenergize the power supply circuit when said machine is tilted, for servicing, to a position wherein one of said other switching means will become closed.

13. In a machine of the class described having a movable carriage and a platen frame mounted on said carriage for movement between an operating position and a throwback position, electrically operated actuating means mounted on said carriage, means for coupling said actuating means with said platen frame to said platen frame to throwback position upon said actuating means being energized, switching means for connecting said actuating means in circuit with a source of electrical energy, latching means automatically latching said platen frame in throwback position, and means for selectively rendering said latching means ineffective during throwback operations of said platen frame whereby said platen frame will remain in throwback position only as long as said switching means is closed.

14. In a machine of the class described having a movable carriage, a platen frame mounted on said carriage for movement between a printing position and a throwback position, and a feed throat movable between a closedthroat and open-throat condition, electrically operated actuating means mounted on said carriage and coupled to said platen frame and adapted, when energized, to move said platen frame from said printing position to said throwback position, switching means for connecting said platen frame actuating means in circuit with a source of electrical energy, throat actuating means to open said throat as an incident to throwback movement of said platen frame and to close said throat as an incident to return movement of said platen frame, latching means automatically latching said platen frame in throwback position, and means for selectively rendering said throat actuating mechanism and said latching mechanism ineffective during throwback operation of said platen frame whereby said platen frame will remain in throwback position only as long as said switching means is closed and whereby said feed throat will remain closed during said throwback operation of said platen frame.

15. In a machine of the class having a movable carriage and a platen frame mounted on said carriage movable between a printing position and a throwback position, releasable latching means for locking said platen frame in throwback position, power means mounted on said carriage and operatively coupled to said platen frame and adapted, when energized, to move said platen frame from said printing position to said throwback position, power means connected to said latching means operable, when energized, to disable said latching means, and means for connecting operating power to said first and last named power means including means for selectively controlling the flow of operating power to said power means for moving the platen frame and said power means for disabling said latching means.

16. In a machine of the class having a movable carriage and a platen frame mounted on said carriage movable between a printing position and a throwback position, electromagnetic means of the rotary type having high initial and relatively low final torque mounted on said carriage for rotary movements of its output member about an axis substantially parallel with the direction of movement of said carriage and operatively coupled to said platen frame and adapted, when energized, to move said platen frame from said printing position to said throwback position, and manually operable switching means for connecting said electromagnetic means in circuit with a source of energization.

References Cited in the file of this patent UNITED STATES PATENTS 2,202,595 Muller May 28, 1940 2,332,033 Welker Oct. 19, 1943 2,558,947 Furman July 3, 1951 FOREIGN PATENTS 160,771 Switzerland June 1, 1933 

